A photosensitive material generally has silver halide emulsion layers light-sensitive to three primary colors of blue, green, and red, and it forms a dye image according to so-called subtractive color photography, in which a dye image is formed by color-forming three kinds color-forming materials (couplers) in these silver halide emulsion layers in relation of complementary colors to the color to which each of the above layers is intrinsically sensitive. The dye image that is obtained by photographic processing of this photosensitive material is generally formed from any of azomethine dyes or indoaniline dyes formed by a reaction between an oxidation product of an aromatic primary amine color-developing agent and a coupler. The thus-obtained color photographic image is not fully stable against light and wet heat, such that the color (dye) image exposed to light, or stored under high-temperature and high-humidity conditions for a long period of time, fades or discolors, which results in deterioration of image quality.
Fading or discoloring of the image is almost a fatal disadvantage for a recording material. As methods to eliminate such disadvantages, various techniques are proposed, such as development of couplers that enable providing a dye excellent in fastness, use of anti-fading agents, and use of ultraviolet-absorbing agents to inhibit an image from deterioration owing to ultraviolet radiation. Among these techniques, the effect of inhibiting an image from deterioration that is obtained by using anti-fading agents is remarkable. For example, it is known to use anti-fading agents, such as hydroquinones, hindered phenols, catechols, gallic acid esters, aminophenols, hindered amines, chromanols, indanes, ethers or esters that are formed by silylation, acylation, or alkylation of a phenolic hydroxyl group of each of these compounds, and metal complexes.
Even though these compounds are recognized as effective agents to inhibit a dye image from fading and discoloring, they are inadequate to respond to customer demand for high image quality. Further, these compounds fail to exhibit synthetically excellent effects that are useful for color photography, because they sometimes cause a hue change, or generate fog, or cause dispersion failure, or produce fine crystals after emulsion coating. Further, to obtain high image quality, sometimes a large amount, or multiple kinds, of compounds are used. Consequently, sometimes it takes a long time to perform processing, which results in difficulty obtaining a sufficient developed dye density. Also from the viewpoint in the aforementioned aspects, development of improved inhibitors has been desired. On the other hand, recently it has been known to use acrylate compounds and compounds derived from them as inhibitors of dye deterioration, as described, for example, in JP-A-8-44020 (“JP-A” means unexamined published Japanese patent application), JP-A-11-258748, and JP-A-11-327101. However, these compounds are unsatisfactory, since they are insufficient in preventing image deterioration, or they adversely affect photographic properties. Further, even though the compounds described in JP-A-6-59390 are effective for resistance against yellowing at the time of processing, they are insufficient to prevent image deterioration.
In silver halide photographic photosensitive materials (hereinafter also referred to simply as “photosensitive materials”) for subtractive color photography, a color image is formed by dyes of three primary colors of yellow, magenta, and cyan. In a color photographic material, (in particular a color print material for direct appreciation, which is used in the color photography that uses a current p-phenylenediamine-series color-developing agent, use is made of an acylacetanilide-series compound as a yellow dye-forming coupler (hereinafter “a dye-forming coupler” is also referred to simply as “a coupler”). However, the hue of yellow dyes obtained from these dye-forming couplers is reddish, due to an inferior sharpness of a peak of the absorption curve at the longer wavelength side (that is, on the absorption curve, the peak in interest has subsidiary absorption at its foot portion at the longer wavelength side), and it is difficult to obtain a yellow hue with high purity. Further, the above-mentioned dyes are sometimes easily decomposed under conditions of high temperature and high humidity, or of irradiation of light, and thus they have insufficient image storability after development processing. Further, because the molecular extinction coefficient of the dye is low, large quantities of the coupler and silver halide are needed to obtain a desired color density, which results in an increase in the film thickness of the photosensitive material. Such increased film thickness sometimes reduces sharpness of the dye image, and also becomes a serious hindrance to the rapid processing that has been strongly utilized in recent years. In this situation, improvement of these performances has been desired.
In order to solve these problems, improvement of acyl groups and anilido groups were proposed on the couplers. Recently, as improved couplers of the conventional acylacetanilide-series couplers, there were proposed, for example, 1-alkylcyclopropanecarbonyl acetanilide-series compounds, cyclomalondiamide-type couplers, pyrrole-2- or 3-yl- or indole-2- or 3-yl-carbonylacetanilide-series couplers. The dyes formed from these couplers were improved in terms of both hue and molecular extinction coefficient of dyes formed, compared with the conventional ones. However, these improved couplers are not satisfactory in image storability still. Further, owing to their complicated chemical structure, the synthesis route became longer, and consequently cost of the couplers became higher, causing a practical problem.
On the other hand, in recent years, acetic acid ester-series and acetanilide-series couplers, to which 1,2,4-benzothiadiazine-1,1-dioxide is bonded, are proposed, for example, in U.S. Pat. No. 3,841,880, JP-A-52-82423, and JP-A-2-28645. These couplers, however, are low in color-forming property, and they are inferior in sharpness of a peak of the adsorption curve owing to the subsidiary absorption at the foot portion on the longer wavelength side. Further, acetic ester-series and acetanilide-series couplers, to which 1,2,4-benzothiadiazine-1,1-dioxide is bonded, as described in European Patent Publication No. 1246006, are remarkably improved in these points, and thereby these couplers give dyes having high color-forming property and provide excellent absorption characteristics. Nonetheless, dyes obtained from these couplers are insufficient in fastness to light at low-density areas, under conditions of storage at high temperature. Therefore, there is a need to improve light fastness at a low-density area, particularly when a picture is exposed to light under high-temperature storage conditions (for example, the situation seen regarding displays in a commercial photo studio). Because a low density of yellow is employed for image reproduction of a human face, light fastness in such a density region is important. The bisphenol-series image-stabilizing agents described in EP-A-1246006 and the like still do not perform adequately under such severe storage conditions. On the contrary, reduction in color density and deterioration of processing stability with a running solution are seen with addition of the bisphenol compound. Therefore, further improvement has been desired.